Cast internal-combustion heater



March 1947. H. J. DE N. MCCOLLUM 2,417,315

CAST INTERNAL COMBUSTION HEATER FOR HEATING AIR Filed July 29, 1942 3Sheets-Sheet l IHLL/ zi i March 1947. H. 4.135 N. MCCOLLUM 2,417,315

CAST INTERNAL COMBUSTION HEATER FOR HEATING AIR Filed July 29, 1942 3Sheets-Sheet 2 March 11, 1947. H. J. DE N. M COLLUM 2,417,315

V CAST INTERNAL COMBUSTION HEATER FOR HEAT ING AIR Filed July 29, 1942 3Sheets-Sheet 3 fzadezazazf mary considerations.

Patented Mu. 11, 1947 UNITED STATES IPATNT; OFFICE CASTINTERNAL-COMBUSTION HEATER FOR HEATING AIR Henry J. De N. McCollum,Chicago, 111.; Thelma McCollnm, executrix of said Henry]. De N.McCollum, deceased, assignor to Stewart- Warner Corporation, Chicago,111., a corporation of Virginia Application July 29, 1942, Serial No.52,707

8 Claims. (Cl- 126-410) The present invention relates to heaters of theinternal combustion type, and more particularly to a heater or this typewell adapted, be-

cause of its high heat output considering its size and weight, to use inaircraftand other vehicles where the Weight and size of equipment One ofthe objects of the present invention is to provide an improved heaterwhich may be constructed as a small integral unit at comparatively lowcost.

Yet another object of the present invention is to provide a novelinternal combustion heater in which the principal structural element canbe formed as a single casting.

Still another object of the present invention is to provide a novel,small, inexpensive internal combustion heater having improved safetymechanism to prevent overheating.

Other objects and advantages will become apparent from the followingdescription of a preferred embodiment of my invention.

In the drawings, in which similar characters of reference refer tosimilar partsthroughout the several views:

are pri- The heater of the present invention includes an inlet fittingl0 hreaded to receive a connection leading to a ource of combustiblemixture. This fitting includes a butterfly valve, not shown, but whichis mounted upon a transversely extending rotatable shaft I2. The shaftand valve are biased by a coil spring It to revolve toward closedposition, and are normally held in open position by a latch l6 whichimpinges against a detent 18. to be described more fully presently. Thelatch 16 is formed in the edge of a disc 20 secured to thebutterflyvalve shaft l2, this disc also having a small hole 22 throughwhich one end of the coil spring I4 is hooked, the other end of thespring being held in fixed position by any suitable means. At anotherportion, the disc also has an outwardly extending lug 24 which impingesagainst a pin 26 when the valve shaft I2 is revolved approximately 90from its open position.

into-a position with the stop lug 24 against the pin-28. In suchposition the butterfly valve extends across the bore through the fitting10, thus Fig. 1 is a side elevation of a heater embodying the presentinvention, with a portion of the housing thereof broken away toillustrate the position of an air circulating fan;

Fig. 2 is a left end elevation shown in Fig. 1;

Fig. 3 is a vertical, transverse sectional view which may be consideredas taken substantially along the line 3-3 of Fig. 1 in the direction ofthe arrows;

Fig. 4 is a horizontal, medial sectional view through the outlet portionof the heater and may be considered as taken along the line 4-4 of Fig.5 looking downwardly, as indicated by the arrows;

Fig. 5 is a vertical, longitudinal sectional view taken in the directionof the arrows along the line 5-5 of Fig. 2;

' Fig. 6 is a plan view of a casting forming one of the principalelements of the heater of the present invention; and Fig. 7 is afractional, detail sectional view drawn to larger scale and may beconsidered as taken along the line 1-1 of the arrows. v

01' the heater Fig. 5 in the direction of ,fsubstantially preventing theflow of combustible mixture therethrough. -In order to open the valve,therefore, it may be manually rotated into the position best shown inFig. 2, with the latch I 6 hooked behind the detent l8, theparts beingadapted to yield resiliently o as to permit the detent to snap intoengagement with the latch.

As long as this 'detent remains in place, therefore,

the butterfly valve will extend vertically within 5 the bore through theinlet fitting I 0, thus per- 40 plurality of radial ports 28 formed bystriking vanes outwardly from the cylindrical member 30, the lower endof this cylindrical member being closed by a generally conical plug 32.Combustible mixture moving downwardly through the fitting I0, therefore,will strike the conical plug 32 and will flow outwardly through theradial ports 28. Inasmuch as the vanes are struck outwardly at an angle,the combustible mixture will leave the fitting I0 with a swirlingmotion.

At a point somewhat above the radial ports 40. The casting 40 provides,when assembled with other elements, a combustion chamber 42, an exhaustoutlet passage 44 separated from-the chamber 42 by an inwardly extendingrib 54, a

plurality of circular parallel passages 46 in the form of groovesbetween ribs 52 for conveying the hot products of combustion from thecombustion chamber 42 in clockwise direction in Fig. 3 to the exhaustpassage 44, and a plurality of outwardly directed heat exchange fins '48which interchange the heat from the hot productsof combustion to the airto be heated.

In general, the casting 40 comprises a cylindrical central section 50,the upper portion of the wall of which is ofiset outwardly to providethe longitudinally extending combustion chamber 42 and the exhaustchamber 44.

The ribs 52 are closely spaced and extend circumierentially fromaposition closely adjacent the combustion chamber 42 around the innercircumference of the casting to an outlet passage 44, the wall portionof the casting forming the outlet passage being threaded to receive afitting 63. This outlet passage 44 isclosely adjacent to the combustionchamber 42, communication directly between these two openings in'theinner circumference being blocked by said inwardly extending rib 54 ofthe casting whichhas its inner face the same radial distance from'thecenter line of the casting as the inner edges of the ribs 52. Theexhaust passage 44 extends longitudinally and is substantiallycoextensive in length with the combustion chamber 42, and both of thesechambers are coextensive longitudinally with the circumferentiallyarranged passages 46 allot which communicate at both ends with thechambers 42 and 44.

The generally cylindrical opening or recess ;in the casting 40 is closedat one end by an endpiece 56 formed as a portion or the casting. Theother end of the opening is closed by a cover 68 and gasket 63 securedin place by screws 60 so as to hold a cylindrical sleeve 62 in positiontherein. This sleeve has approximately the same diameter as the internaldimension of the casting and, therefore, serves as a partial closure forthe inner faces of the passages 46. It also, acting in conjunction withthe inwardly extending tion chamber 42 from the outlet passage 44'excepting by way of the passages 46.

The sleeve 62 is perforated by a multiplicity of longitudinallyextending slots 64 arranged in .rows, the slots in adjacent rows beingstaggered,

as is best illustrated in Figs. 4 and 5. These slots extendvcrosswise orthe passages 46 so that the intersecting passages and slots form amultiplicity of small, generally rectangular openings communicatingbetween the passages 46 and the interior of the sleeve. The interior ofthe sleeve is packed with stainless steel wool 65, or other acousticdamping material, so that the structure acts as a mufller-that is, itdamps out the noise accompanying operation and smooths out pulsationswhich otherwise might. produce the effect known as motor boating.

The combustible mixture flowing into thecombustion chamber 42 is ignitedby an igniter'plug 468 or the hot wire type, threaded "into anoiicningformed in the portion oi the casting above the combustion chamber 42.

The principal operating element of the igniter :plug is a spirally woundcoil 66, which, when electrically-energized, is heatedto atemperaturesuflicient to-inltiate the burning of the combustiblemixture. After the heater warms up somewhatrthe igniter can bedeenergized inasmuch as .a reigniter 69, 'formed of a looselycoiledsheet-of Inconel :or other heat vand corrosion resistant'metal, acts toreestablish combustion if combustion should for' any reason fail."This'reigniter is described in, greater detail in my :Patent- No.2,396,868, :and for convenience, is secured to the lower end act thefitting ill belowtheradialports'28.

A thermostatic .element 10, located in an opening in the end -oi thecasing 4.0, acts as an overheat switch and operates a solenoid valve toshut on the flow of combustible 'mixturetif'the heater becomesabnormally .hot. The solenoid valve is not .shown, but-:isconnected.inthesupply conduit connected-to theinlet fitting l0.

Substantially the entire circumference of the cylindrical portionfSll of:the casting 40 is provided with the longitudinally extending flns46,

-'previously mentioned. At two .points a pair of rib 64, serves as apartial closure for the combuslegs 12 extend outwardlyfrom the centralportion '50 and support :the outer cylindrical shell "36, the shellbeing secured'tothese'legs by screws 14. In general, the legs 312 areequally spaced clrcumferentlally from eachother and fromthe up- .perportion of "the casting :into which the inlet .fitting Ill andignitera-plug -66:are threaded. The

.shell36. also rests against this upper portion, thus giving the shellthree-points of-securem'ent 'to the casting located in its interior,thus providing rigid structure.

The'forward oroutlet end of "theshell '36 at the left in Fig. '5 isapproximately coextensive with the end of the casting 40, while :at itsrearward end the shell extends somewhat beyond the casting toprovidespace for a fan 16 driven by .an electric :motor 18 mounted upona; spider '80'secured to theshell 36. Thus, when'themotor I8 isenergized torotateithe ian'16,,airis :drawn inwardly around .the motor:and is passed forwardly between .the fins 48, :thereby providing a goodinterchange 'of- .heat from the combustion chamber and passages 46-itothe air stream.

The previously mentioned latching detent I8.

is formed from a piece of .sheetmetal =16 and extends downwardly from:its position behind the latch I6, around :the-pin :26, and to the left,

as seen in Fig. 2. Ashort distance from the-'pin,, it is bent downwardlyto :form anzabutment which rests against the side Walker the case.Shortly 1 plug 86 is made depends upon the operationv characteristics ofthe particular heater. This metal should be so-chosen that .under normalconditions the heater .neveribecomes sufliciently hot to melt this plug,but abnormal conditions, which may arise if, for instance,,the-fan'l6should stop and the overheatfswitch :10 -failslto operate,

will result in the plug 86 being melted before the heater becomesdangerously hot. The fusible plug is, therefore, .a safety provision inaddition tothat provided by the overheat switch 10.

, Upon the melting or this plug, the inner end of the pin 84. isnolonger restrained, and the lower end of the sheet metal member 19flies outwardly under the influence of the spring M which rotates thevalve in the inlet passage into closed position in the manner previouslymentioned.

It will be seen that a heater constructed in the manner described andillustrated is extremely economical to manufacture, inasmuch as thesingle casting 40 provides the principal operating elements inconjunction with such accessories as the cylindrical perforated sleeve62, the valve Hi, the igniter 66, the fan and motor 16 and I8, and theextremely simple safety device comprised of the sheet metal member 19,the pin and the fusible plug 86.

While I have shown and described a particular embodiment of myinvention, it will be apparent to those skilled in the art that numerousmodidrical recess intersecting said combustion cham-.

her, said casting also providing a longitudinally extending outletpassage at one side adjacent said combustion chamber, said castinghaving a plurality of circumferential parallel grooves extending fromsaid combustion chamber to said outlet passage and'passing around themajor portion of the circumference of said cylindrical vrecess, and asleeve fitted into said cylindrical recess to close said grooves,thereby providing aplurality of circumferentially extending passagesconnecting said combustion chamber to said outlet passage.

2. In an internal combustion heater a generally cylindrical casting,said casting having a longitudinally extending combustion chamber at oneside and a longitudinally extending cylindrical recess intersecting saidcombustion chamber, said casting also providing a longi-' tudinallyextending outlet passage at one side adjacent said combustion chamber,said casting having a plurality of circumferential parallel groovesextending from said combustion chamber to said outlet passage andpassing around the major portion of the circumferenceof said cylindricalrecess, a sleeve fitted into said cylindrical recess to close saidgrooves, thereby pro-- viding a plurality of circumferentially extendingpassages connecting said combustion chamber'to said outlet passage, saidsleeve havinga plurality of longitudinally extending slots in the sidewall thereof, and a quantity of acoustic damping material located withinsaid sleeve.

3. In an internal combustion heater, a gen erally cylindrical casting,said casting providing a longitudinally extending combustion-chamber atone side and a longitudinally extending cylindrical recess intersectingsaid combustion chamber, said casting also providing a longi-' .6 atu'dinally extending outlet passage at oneside adjacent said combustionchamber, said casting :having a plurality of circumferential parallelgrooves extending from said combustion chamber to said outlet passageand passing around the major portion of the circumference of saidcylindrical recess, a sleeve fitted into said cylindrical recess toclose said grooves, thereby providing a plurality of circumferentiallyextending passages, said sleeve having a plurality of slots in the sidewall thereof extending transversely of said grooves, a quantity ofacoustic silencing material located within said sleeve, an .inletfitting attached to said casting for conveying combustible mixture tosaid combustion chamber, thermostatic means for shutting off the flow offuel. to the heater when the casting becomes abnormallyhot, and otherthermostatic ,means including a fusible member for shutting off. theflow of fuel through said fitting when the heater becomes dangerouslyhot.

4. In an internal combustion heater, a generally cylindrical casting,said casting providing a longitudinally extending combustion chamber atone side and a longitudinally extending cylindrical recess intersectingsaid combustion chamber, said casting also providing a longitudinallyextending outlet passage at one side adjacent said combustion chamber,said castin having a plurality of circumferential parallel groovesextending from said combustion chamber to said outlet passage andpassing around the major portion of the circumference of saidcylindrical recess, .a sleeve fitted into said cylindrical recess toclose said grooves, thereby providing a plurality of circumferentiallyextending passages, a plurality of longitudinally extendingheat exchangefins formed upon the outer sur face of said casting, a shell enclosingsaid fins, and air circulating means to circulate air to .be heatedthrough said shell.

5. In an interna1 combustion heater, a generally cylindrical casting,said casting providing a longitudinally extending combustion chamber atone side and a longitudinally extending cylindrical recess intersectingsaid combustion chamber, said casting also providing a longitudinallyextending outlet passage" at one side adjacent said combustion chamber,said casting having a plurality of circumferential parallel groovesextending from said combustion chamber to said outlet passage andpassing around themaior portion of the circumference of said cylindricalrecess, a sleeve fitted into said cylindrical recess to close saidgrooves, thereby providing a plurality of circumferentially extendingpassages,

said sleeve having a plurality of slots in the side wall thereofextending transversely of said grooves, a quantity of acoustic silencingmaterial located within said sleeve, a plurality of longitudinallyextending heat exchange fins formed upon the-outer surface of saidcasting, a shell enclosing said fins, and air circulating means tocirculate air to be heated throughsaid shell. 6. In an internalcombustion heater, the

combination of a casting having a generally cylindrical recess therein,a sleeve in said recess in spaced relation to the wall of the casting, a

longitudinally extending rib interrupting the space between the castingand the sleeve at one side of said recess, said casting having a cavitysubstantiallybounded at one side by said sleeve and providing acombustion chamber at one side -of said rib, said casting having anothercavity forming an outlet passage at the opposite side 7 v 0! said rib,said casting being formed to provide a plurality of slots extendingeircumterentially i'rom said combustion chamber cavity to said outletpassage cavity, said slots being bounded on their open sides by saidsleeve so that said sleeve and said slots together provide a. pluralityof passageways connecting said combustion chamber to said outletpassage, and means 1 to supply fuel to said combustion chamber cavity.

HENRY J. DE N. MccOLLUM.

REFERENCES crrnn The following references are of record in the file ofthis patent:

annexe 8 1111mm s'ra'ms mm Number I Number British Mar. 13, 1930

